Blade assembly for a troweling machine



July 5, 1966 H. w. KELLEY 3,259,033

BLADE ASSEMBLY FOR A TROWELING MACHINE Filed June 1.2, 1965 2 Sheets-Sheet 1 INVENTOR. H E RSCHE LL W. KELLEY i amw ATTORNEYS July 5, 1966 H. w. KELLEY BLADE ASSEMBLY FOR A TROWELING MACHINE 2 Sheets-Sheet 2 Filed June La 1.96?

INVENTOR. HERSCHELL W. KELLEY ATTORNEYS United States Patent 3,259,033 BLADE ASSEMBLY FOR A TROWELING MACHINE Herschel] W. Kelley, 312 Dixie Road, Forest Park, Ga.

Filed June 12, 1963, Ser. No. 287,265

3 Claims. (Cl. 94-45) This invention relates to concrete troweling machines, and is more particularly concerned with an improved blade assembly for a troweling machine.

In the past, blades for troweling machines have included a blade rigidly attached to an arm, with the arm fixed in place on the machine. This gives a cantilever arrangement and the weight of the machine tends to force the outer tips of the blades up, causing only the inner ends of the blades to be effective in working on the concrete.

With only a small surface of each blade in working engagernent with the concrete, there is a greater force per unit area of the blades, since the weight is constant and the surface area is reduced. This greater force has adverse elfects in that it causes the blades to dig into the concrete leaving ridges that must be removed by hand troweling. If a blade engage a rock, or pIece of aggregate, the large force exerted on the rock by the blade will frequently pull the rock across the surface of the concrete, causing a large hole or scratch that must be repaired.

A troweling machine is guided by tilting or canting the machine so that the forces around the circular area being worked are unbalanced, and the machine moves as a result of the unbalanced forces. Such a procedure with the conventional troweling blades will cause the outer tips of the blades to dig into the concrete on the lower side, while the blades on the higher side may be completely ineffective.

The device of the present invention overcomes the abovementioned problems by providing a blade assembly having a shaft which is received in the conventional machine in the conventional manner. The blade itself is pivotally mounted on the shaft so as to pivot about the transverse center line of the blade. This pivotal mounting allows the blade to adapt to various configurations of the surface of the concrete as well as to various cantings of the machine. An even pressure is distributed throughout the entire length of the blade, which gives a greater effective working surface and wearing surface, .as well as a better quality finish on the concrete.

These and other features and advantages of the invention will become apparent from consideration of the following specification when taken in conjunction with the accompanying drawings in which:

FIG. 1 is .a perspective view of a conventional troweling machine having blade assemblies made in accordance with the present invention installed thereon.

FIG. 2 is a perspective view of a float blade made in accordance with the present invention.

FIG. 3 is a perspective view of a troweling blade mounted on an arm.

FIG. 4 is a longitudinal cross sectional view of the troweling blade shown in FIG. 3 and showing the mounting means of the arm to the machine.

FIG. 5 is a cross sectional view taken substantially along the line 55 in FIG. 4, but showing the blade tilted for use.

Referring-now more particularly to the drawings, FIG. 1 shows a conventional troweling machine including a motor 10, such as a gasoline engine, fastened to a base 11. A shaft 12 is driven by the motor and, the shaft 12 carries a cylindrical hub 14 at its lower end. The shafts of the blade assemblies 15 are received in sockets in the hub 14, as will be discussed later.

There is a ring 16 surrounding the blades 15, the ring 3,259,033 Patented July 5, 1966 "ice 16 being supported from the base 11 by rods 18. A handle 19 is attached to the device for controlling the machine.

All of the above is conventional and is well known in the art; therefore, the brief description should suffice.

In curing concrete, the concrete must be agitated in order to cause the aggregate to sink below the surface of the concrete, and to cause a grout comprising sand and cement to rise to the surface of the concrete. The troweling causes the agitation required. When the concrete is relatively soft, a large blade must be used on the troweling machine. This large blade is called a float blade, and is shown in FIG. 2 of the drawings. After the concrete has been cured to the point that the surface has a good level of grout, a trowel blade is used. The trowel blade is smaller than the float blade, giving a greater pressure per unit area on the surface of the concrete. The trowel blade binds the sand and cement together to produce a hard, smooth surface. The trowel blade is shown in FIG. 3 of the drawings.

Both the float blade and the trowel blade are used with the present arrangement. The basic problems are the same with both blades, and the solution to these problems is the same with both blades. The following description will be confined primarily to the trowel blade as shown in FIGS. 3-5.

The trowel blade includes a rectangular blade 20 made of sheet material, usually a spring steel, and turned up at each end as at 21 and 22. Centrally of the blade 20 there is a rectangular tubular housing 24. The housing 24 is trapezoidally shaped in side elevation and has the longer base 26 attached to the blade 20 as by rivets 25.

The blade 20 with its housing 24 is carried by an arm 28. The innermost end 29 of the arm 28 is round so that it can be received in the conventional hub 14, as best shown in FIG. 4. There is a circumferential groove 30 in the end 29, the groove 30 receiving the tip of a retaining screw 31 to prevent axial movement of the arm 28. Outside of the hub 14 and adjacent thereto, a collar 32 is fixed to the end 29 by a set screw 34. An adjusting arm 35 is fixed to the collar 32. The adjusting arm 35 is directed upwardly and is engaged by an adjusting ring 36. As is well known in the art, the adjusting ring 36 can be moved up or down. When moved down, the ring 36 rotates the adjusting arm 35, hence collar 32, hence arm 28. The weight of the machine tends to lay the blades 20 flat which will rotate the arm in one direction; therefore, the arm 35 needs to urge the blades in only one direction. This arrangement is well known in the art.

The arm 28 i received in the housing 24 and carries the housing 24 by a pivot pin 38. The pin 38 passes through both side walls 39 and 40, and the arms 24. Cotter pins 42 or the like hold the pin 38 in place.

The float blade has not been described in detail; but, the construction is substantially the same as the trowel blade, and the equivalent parts are designated with prime reference numerals.

From the foregoing description, operation of the device should be obvious.

To install the blades of the present invention on a machine, the screws 31 must be loosened and the old blade removed. The collar 32 is then removed from the old blade by loosening the set screw 34, and the collar 32 is placed on the portion 29 of the arm 28 as shown in FIG. 4. The arm 28 is then inserted into the hub 14 and the screw 31 is tightened to hold the arm in place.

The float blade 20' is the first blade required in curing concrete; therefore, the outer end of the arm 28 is slipped into the housing 24' of the float blade, and a pin 38 is passed through the walls 39 and 40' of the housing, and through the arm 28.

The adjusting ring 36 is positioned to fix the blade at the desired angle for the condition of the concrete, and work is done in the usual manner. Though only one arm has been described, it will be realized that three such arms and blades will be installed on the machine.

Since there are three blade assemblies 15, the weight of the machine will be evenly distributed among the three blades. The only pressure applied to the blade 20' must be at the pivot pin 38 which is on the centerline of the blade, since that is the only point of contact between the arm 28 and the housing 24'. As a result, the pressure on the blade will be evenly distributed throughout the length of the blade 20'.

With the evenly distributed pressure, if a blade 20 encounter a rise in the surface of the concrete, the blade will adjust by pivoting about the pin 38. If the blade hit a rock or piece of aggregate, the same pressure will be applied to the rock as to other areas of the concrete; hence, the rock will be gently pushed down into the concrete without damaging or scarring the surface of the concrete. When the machine is canted to guide the machine, the blades will pivot to retain full contact along the working edge of the blades, with equal pressure along each of the blades.

It will thus be seen that the working edge of the blade is always held in full contact with the surface of the concrete, giving an even wearing and a large working surface.

The operation of the trowel blade 20 is the same as described above. To change to the trowel blade, one must simply remove the pin 38, slip the float blade 20 off the arm 28, and replace it with the trowel blade 20. Replacement of the pin 38 completes the changeover.

Both the float blade 20' and the trowel blade 20 are symmetrical about their longitudinal center lines; therefore, either edge can be used. When one side of the blade has become worn beyond usefulness, the blade can be turned around so that the opposite edge can be used.

The machine hown in FIG. 1 uses a stationary ring 16, and the arms 28 terminate just past the pivot pin 38. If a floating ring is to be used, the arms 28 must be made longer so as to extend outwardly past the outer tip of the blades 20, 20' so the floating ring can be attached to the arms 28.

It will now be seen that the blades of the present inven tion provide means by which the entire working edge of the blade is against the surface of the concrete, giving a considerably larger working surface than in conventional blades. This distributes the wear on the blade so that a larger area of concrete can be worked with one set of blades, and less time is required since a larger area is worked at any given time. The equal pressure throughout the length of the blades gives a high quality finish to the concrete o that no digging, gouging or the like takes place, and a final finish can be put on the concrete with the troweling machine.

It should be realized that the particular device here presented is by way of illustration only, and is meant to be in no way restrictive; therefore, numerous changes and modifications may be made, and the full use of equivalents resorted to without departing from the spirit or scope of the invention as outlined in the appended claims.

I claim:

1. A troweling machine including a central rotatable hub, radial arms fixed to said hub for rotation therewith, blade assemblies for each of said arms, a transverse pivot for pivotally mounting each blade assembly on each arm, and a crank arm fixed to each radial arm for rotating each radial arm to tilt the blade pivotally attached thereto.

2. A troweling machine including a central rotatable hub, radial arms fixed to said hub for rotation therewith, blade assemblies for each of said arms, a transverse pivot for pivotally mounting each blade assembly on each arm, and a laterally extending crank arm fixed to each radial arm to tilt the blade pivotally attached thereto.

3. A troweling machine including a central rotatable hub, radial arms fixed to said hub for rotation therewith, blade assemblies for each of said arms, a transverse pivot for pivotally mounting each blade assembly on each arm, and a laterally extending crank arm fixed to each radial arm to tilt the blade pivotally attached thereto, and an adjusting ring, concentric with said hub, engaging all of said laterally extending crank arms for simultaneously adjusting the tilt of all of said blades.

References Cited by the Examiner UNITED STATES PATENTS 446,445 2/1891 Graham 15--50 3,045,267 7/1962 Wagner l550 3,062,107 11/1962 Mitchell 94-45 JACOB L. NACKENOFF, Primary Examiner. 

1. A TROWELING MACHINE INCLUDING A CENTRAL ROTATABLE HUB, RADIAL ARMS FIXED TO SAID HUB FOR ROTATION THEREWITH, BLADE ASSEMBLIES FOR EACH OF SAID ARMS, A TRANSVERSE PIVOT FOR PIVOTALLY MOUNTING EACH BLADE ASSEMBLY ON EACH ARM, AND A CRANK ARM FIXED TO EACH RADIAL ARM FOR ROTATING EACH RADIAL ARM TO TILT THE BLADE PIVOTALLY ATTACHED THERETO. 